Glass inspection is applied in many fields, especially in the field of mobile phone display panel, iPad window panel and flat-panel display manufactures. Due to difficultly for taking high quality images on different defects (scratches, crashes, black/white defects, lack, cracks, pin-holes, concave edges and raised edges, bubbles and smudges) on the surface, backside and mid-layer of glasses, therefore in the world, no full automatic glass inspection system provides high quality inspection solution, thus the method of human manual inspections is still used in most glass manufactures. The inspection accuracy of this method is limited by the vision of human beings and the inspection results of this method can become not reliable due to human errors from human's feeling, emotion and tiredness.
Among the current automatic glass detection technology, there are some apparatus that can photograph one or several defects, but it still lacks a consistent, stable, fast, and high accuracy glass photographing apparatus, and the method for creating the same.
Among the current automatic glass detection technology, most of glass photography devices use multiple area scanning cameras for high accuracy photography, but this technique is restricted at its mechanical mounting space when photographing small size glasses such as mobile phone glass panel. This invention uses multiple line-scanning cameras with micro-lens to walk around the problem of space limit.
Among the multiple layer glass photography of the invention, multiple layer photography for scratches on glasses is most difficult. So far there is no single apparatus that can photograph glass scratches at all orientations. For instance, one apparatus is able to take clear photographs to expose scratches on glasses on vertical direction (+/+30°) but not on horizon direction, and another apparatus is able to take clear scratch photographs on glasses on horizon direction (+/−30°) but not on vertical direction. To solve the glass photograph problem that it is difficult to get clear photographs to expose scratches on all orientations, this invention introduces an apparatus that adopts an illumination technology using multiple lights to spread on the glass from different positions and various angles.
Most of machine-vision applications take one photograph of glass panel for image process and inspection. The apparatus of this invention introduces flexible hardware architectures. Using the apparatus of this invention, it can take one or multiple photo-images for each glass panel based on the glass inspection need of customer, and each photo-image can capture clear image of one or more defects in various layers. This results in fast inspections of multiple-layered glass with the support of multi-tasking image process and inspection.
On normal machine vision applications, the photographing hardware is usually fixed, and is not easy to modify. This invention introduces a flexible hardware architectures for various glass inspecting purposes.
There are two methods to take photo-image on glasses. One is fixing glasses and move cameras, and the other is fixing cameras and moving glasses. The later method is used in this invention.
To control photographing and real-time inspection at multiple glass layers, multi-tasking photographing, image processing and inspection techniques software must be programmed.